I changed the battery in my 97 remote and it didn't work, so I held lock and unlock for 10 seconds and got the horn honk confirming relearn.

Now my question. If I'm in the parking lot with other c5s (or any Chevy of that era using that system) can I hold lck+unlock to "relearn" my fob to a random car and unlock it?

Or more importantly, can they use this technique to get into mine?

 

No, I believe that the C5 has a roaming code, It changes every time you use it,
Your fob has to be mated with your receiver.

 

You didn't relearn your code when you held it down, you only resynched it to an already programmed fob. Relearn (reprogram) requires turning on the key and going through the fob program procedure in the DIC. It wouldn't be much of a security system if it was that easy. What you did was resynch the rolling code used by the car and the fob to communicate.

 

I see that explains it. Makes me feel better. I have in the past used the FOB training on the DIC. Didn't realize there was a difference between the two methods or that it was a rolling code.

Good to know.

 

So I'm reading through this post out of casual interest (changed my fob battery, cleaned everything up but still no joy) and realized that maybe my fob is not working because I didn't relearn it. So I did the 'search', found the procedure and got it to work!

Lesson learned?? Read all the posts because you never know when you will have an 'Ah haa' moment!